package com.atguigu.gulimall.seckill.service.impl;

import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.atguigu.common.to.mq.SeckillOrderTo;
import com.atguigu.common.utils.R;
import com.atguigu.common.vo.MemberRespVo;
import com.atguigu.gulimall.seckill.feign.CouponFeignService;
import com.atguigu.gulimall.seckill.feign.ProductFeignService;
import com.atguigu.gulimall.seckill.interceptor.LoginUserInterceptor;
import com.atguigu.gulimall.seckill.service.SeckillService;
import com.atguigu.gulimall.seckill.to.SeckillSkuRedisTo;
import com.atguigu.gulimall.seckill.vo.SeckillSessionsWithSkus;
import com.atguigu.gulimall.seckill.vo.SkuInfoVo;
import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import com.sun.deploy.security.BlockedException;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RSemaphore;
import org.redisson.api.RedissonClient;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.BoundHashOperations;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

import java.math.BigDecimal;
import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

@Service
@Slf4j
public class SeckillServiceImpl implements SeckillService {

    @Autowired
    private CouponFeignService couponFeignService;

    @Autowired
    private StringRedisTemplate redisTemplate;

    @Autowired
    private ProductFeignService productFeignService;

    @Autowired
    private RedissonClient redissonClient;

    @Autowired
    private RabbitTemplate rabbitTemplate;

    private final String SESSIONS_CACHE_PREFIX = "seckill:sessions:";
    private final String SKUKILL_CACHE_PREFIX = "seckill:skus:";
    private final String SKU_STOCK_SEMAPHORE = "seckill:stock:";// +商品随机码

    @Override
    public void uploadSeckillSkuLatest3Days() {
        // 1、扫描最近三天需要参加秒杀的活动
        R session = this.couponFeignService.getLatest3DaySession();
        if (session.getCode() == 0) {
            // 上架商品
            List<SeckillSessionsWithSkus> sessionData = session.getData(new TypeReference<List<SeckillSessionsWithSkus>>() {});
            // 将数据缓存redis
            // 1、缓存活动信息
            this.saveSessionInfos(sessionData);
            // 2、缓存活动的关联商品信息
            this.saveSessionSkuInfos(sessionData);
        }
    }

    public List<SeckillSkuRedisTo> blockHandler(BlockException e) {

        log.error("getCurrentSeckillSkusResource被限流了。。。");
        return null;
    }

    /**
     * 返回当前时间可以参与的秒杀商品信息
     * @return
     */
    @Override
    @SentinelResource(value = "getCurrentSeckillSkusResource", blockHandler = "blockHandler")
    public List<SeckillSkuRedisTo> getCurrentSeckillSkus() {
        // 1、确定当前时间属于哪个秒杀场次
        long time = new Date().getTime();
        try (Entry entry = SphU.entry("seckillSkus")) {
            Set<String> keys = this.redisTemplate.keys(SESSIONS_CACHE_PREFIX + "*");
            for (String key : keys) {
                String replace = key.replace(SESSIONS_CACHE_PREFIX, "");
                String[] split = replace.split("_");
                Long start = Long.parseLong(split[0]);
                Long end = Long.parseLong(split[1]);
                if (time >= start && time <= end) {
                    // 2、获取这个秒杀场次需要的所有商品信息
                    List<String> range = this.redisTemplate.opsForList().range(key, -100, 100);
                    BoundHashOperations<String, String, String> hashOps = this.redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
                    List<String> list = hashOps.multiGet(range);
                    if (list != null) {
                        List<SeckillSkuRedisTo> collect = list.stream().map(item -> {
                            SeckillSkuRedisTo redis = JSON.parseObject((String) item, SeckillSkuRedisTo.class);
                            return redis;
                        }).collect(Collectors.toList());
                        return collect;
                    }
                    break;
                }
            }
        } catch (BlockException e) {
            log.error("资源被限流，{}", e.getMessage());
        }
        return null;
    }

    @Override
    public SeckillSkuRedisTo getSkuSeckillInfo(Long skuId) {
        // 1、获取到所有需要参与秒杀的商品的key
        BoundHashOperations<String, String, String> hashOps = this.redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);

        Set<String> keys = hashOps.keys();
        if (keys != null && keys.size() > 0) {
            String regx = "\\d_" + skuId;
            for (String key : keys) {
                // 匹配正则：6_4
                if (Pattern.matches(regx, key)) {
                    String json = hashOps.get(key);
                    SeckillSkuRedisTo skuRedisTo = JSON.parseObject(json, SeckillSkuRedisTo.class);
                    // 处理随机码，不应当直接返回
                    long current = new Date().getTime();
                    Long startTime = skuRedisTo.getStartTime();
                    Long endTime = skuRedisTo.getEndTime();
                    if (!(current >= startTime && current <= endTime)) {
                        skuRedisTo.setRandomCode(null);
                    }
                    return skuRedisTo;
                }
            }
        }
        return null;
    }

    /**
     * TODO 上架秒杀商品的时候，每一个数据都有过期时间
     * TODO 秒杀后续的流程，简化了收货地址等信息
     * @param killId
     * @param key
     * @param num
     * @return
     */
    @Override
    public String kill(String killId, String key, Integer num) {

        long l1 = System.currentTimeMillis();

        MemberRespVo respVo = LoginUserInterceptor.loginUser.get();
        // 1、获取当前秒杀商品的详细信息
        BoundHashOperations<String, String, String> hashOps = this.redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);

        String json = hashOps.get(killId);
        if (StringUtils.isEmpty(json)) {
            return null;
        } else {
            SeckillSkuRedisTo redis = JSON.parseObject(json, SeckillSkuRedisTo.class);
            // 校验合法性
            Long startTime = redis.getStartTime();
            Long endTime = redis.getEndTime();
            long current = new Date().getTime();

            long ttl = endTime - current;
            // 1、校验时间的合法性
            if (current >= startTime && current <= endTime) {
                // 2、校验随机码和商品id
                String randomCode = redis.getRandomCode();
                String skuId = redis.getPromotionSessionId() + "_" + redis.getSkuId();
                if (randomCode.equals(key) && killId.equals(skuId)) {
                    // 3、验证购物数量是否合理
                    if (num <= redis.getSeckillLimit().intValue()) {
                        // 4、验证这个用户是否已经购买过。如果秒杀成功，就去占位。
                        String redisKey = respVo.getId() + "_" + skuId;
                        Boolean aBoolean = this.redisTemplate.opsForValue().setIfAbsent(redisKey, num.toString(), ttl, TimeUnit.MILLISECONDS);
                        if (aBoolean) {
                            // 占位成功，说明从来没有买过
                            RSemaphore semaphore = this.redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + randomCode);
                            boolean b = semaphore.tryAcquire(num);
                            if (b) {
                                // 秒杀成功
                                // 快速下单。发送MQ消息
                                String timeId = IdWorker.getTimeId();
                                SeckillOrderTo orderTo = new SeckillOrderTo();
                                orderTo.setOrderSn(timeId);
                                orderTo.setMemberId(respVo.getId());
                                orderTo.setNum(num);
                                orderTo.setPromotionSessionId(redis.getPromotionSessionId());
                                orderTo.setSkuId(redis.getSkuId());
                                orderTo.setSeckillPrice(redis.getSeckillPrice());

                                this.rabbitTemplate.convertAndSend("order-event-exchange", "order.seckill.order", orderTo);

                                long l2 = System.currentTimeMillis();
                                log.info("耗时。。。", (l2 - l1));

                                return timeId;
                            }
                        } else {
                            // 说明已经买过了
                            return null;
                        }
                    }
                } else {
                    return null;
                }
            } else {
                return null;
            }
        }
        return null;
    }

    /**
     * 保存秒杀活动信息
     * @param sessions
     */
    private void saveSessionInfos(List<SeckillSessionsWithSkus> sessions) {

        if (sessions != null) {
            sessions.stream().forEach(session -> {
                Long startTime = session.getStartTime().getTime();
                Long endTime = session.getEndTime().getTime();

                String key = SESSIONS_CACHE_PREFIX + startTime + "_" + endTime;
                Boolean hasKey = this.redisTemplate.hasKey(key);
                if (!hasKey) {
                    List<String> collect = session.getRelationSkus().stream().map(item -> item.getPromotionSessionId() + "_" + item.getSkuId().toString()).collect(Collectors.toList());
                    // 缓存活动信息
                    this.redisTemplate.opsForList().leftPushAll(key, collect);
                }
            });
        }
    }

    /**
     * 保存秒杀活动的商品信息
     * @param sessions
     */
    private void saveSessionSkuInfos(List<SeckillSessionsWithSkus> sessions) {

        if (sessions != null) {
            sessions.stream().forEach(session -> {
                // 准备hash操作
                BoundHashOperations<String, Object, Object> ops = this.redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
                session.getRelationSkus().stream().forEach(seckillSkuVo -> {
                    // 4、随机码
                    String token = UUID.randomUUID().toString().replace("-", "");

                    if (!ops.hasKey(seckillSkuVo.getPromotionSessionId().toString() + "_" + seckillSkuVo.getSkuId().toString())) {
                        // 缓存商品
                        SeckillSkuRedisTo redisTo = new SeckillSkuRedisTo();
                        // 1、sku的基本数据
                        R skuInfo = this.productFeignService.getSkuInfo(seckillSkuVo.getSkuId());
                        if (skuInfo.getCode() == 0) {
                            SkuInfoVo info = skuInfo.getData("skuInfo", new TypeReference<SkuInfoVo>() {});
                            redisTo.setSkuInfo(info);
                        }
                        // 2、sku的秒杀信息
                        BeanUtils.copyProperties(seckillSkuVo, redisTo);
                        // 3、设置当前商品的秒杀时间信息
                        redisTo.setStartTime(session.getStartTime().getTime());
                        redisTo.setEndTime(session.getEndTime().getTime());

                        redisTo.setRandomCode(token);

                        String jsonString = JSON.toJSONString(redisTo);
                        ops.put(seckillSkuVo.getPromotionSessionId().toString() + "_" + seckillSkuVo.getSkuId().toString(), jsonString);

                        // 如果当前这个场次的商品的库存信息已经上架就不需要上架了
                        // 5、使用库存作为分布式的信号量————限流
                        RSemaphore semaphore = this.redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + token);
                        // 商品可以秒杀的数量作为信号量
                        semaphore.trySetPermits(seckillSkuVo.getSeckillSort());
                    }
                });
            });
        }
    }
}
